Pension and Other Postretirement Benefit Plans - Components of Net Periodic Benefit Costs (Credit) (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Foreign
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Curtailment (gain) loss	$ (12.9)
Pension | U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Service cost		$ 0.1	$ 0.1	$ 0.1
Interest cost		18.6	19.8	21.8
Expected return on plan assets		(20.2)	(27.3)	(24.0)
Amortization of actuarial (gain) loss		1.8	2.0	2.6
Curtailment (gain) loss		0.0	0.0	0.0
Settlement losses		0.1	5.7	0.2
Net periodic benefit cost (credit)		0.4	0.3	0.7
Pension | Foreign
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Service cost		6.3	6.9	7.3
Interest cost		14.7	14.7	15.0
Expected return on plan assets		(20.9)	(23.0)	(22.9)
Amortization of actuarial (gain) loss		7.8	6.2	5.1
Curtailment (gain) loss		(2.3)	0.4	0.9
Settlement losses		0.0	0.0	0.8
Net periodic benefit cost (credit)		5.6	5.2	6.2
Other Postretirement | U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Service cost		0.0	0.0	0.1
Interest cost		2.1	1.9	2.4
Amortization of actuarial (gain) loss		(2.3)	(2.2)	(2.6)
Curtailment (gain) loss		0.0	0.0	0.0
Amortization of prior service credit		(0.2)	(0.2)	0.0
Special termination benefits		0.0	0.0	0.0
Net periodic benefit cost (credit)		(0.4)	(0.5)	(0.1)
Other Postretirement | Foreign
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Service cost		0.3	0.4	0.5
Interest cost		1.3	1.4	1.5
Amortization of actuarial (gain) loss		0.0	0.2	0.3
Curtailment (gain) loss		(10.6)	0.0	0.0
Amortization of prior service credit		(0.2)	(0.3)	(0.4)
Special termination benefits		0.0	0.0	0.1
Net periodic benefit cost (credit)		$ (9.2)	$ 1.7	$ 2.0